New ways to improve marine power systems to reduce costs and promote sustainability

Today, owners are looking for new ways to improve their power systems so that they cost less to operate and are more environmentally friendly. One solution that many operators are considering is the adding of a battery or energy storage system to provide hybrid power to meet a vessel’s needs. Such a solution is proving popular in delivering important reductions in fuel costs and meeting the latest emission targets.

Vessels energy storage systemsFor instance, Canadian-based Corvus Energy uses a lithium ion based energy storage system that has been approved by class societies DNV GL, Lloyd’s Register and ABS. In addition, the industry is seeing an increasing number of customers and is requiring vessels to operate meeting latest in emission controls, as a result, growing interest by vessel operators in hybrid solutions to meet growing demand.

In Europe, we are seeing an increasing number offshore support vessels being retrofitted energy storage systems that replace an existing generator. Such an example is the Eidesvik offshore support vessel Viking Princess, which Wärtsilä retrofitted with a Corvus Orca energy storage system in 2017. At the time, Wärtsilä said the adoption of energy storage systems could result in fuel savings of up to 30% and a reduction of CO2 emissions by up to 18% a year.

Elsewhere, in Europe Wärtsilä retrofitting North Sea Shipping AS’ North Sea Giant with an energy storage systems resulting in this becoming the first hybrid offshore vessel dynamic positioning class of DP3. The Wärtsilä website is certainly optimistic about the prospects for its technology, since expects battery capacity will increase tenfold to twentyfold in the next 10 years and that pretty much all short sea challenges can be solved on battery operation, charged from a clean source.

Another fleet owner of offshore support vessels is Louisianabased SEACOR Marine. It recently contracted with Corvus to install energy storage systems on four of its

Seacor Marine is another pioneer in this area, having earlier this year contracted Corvus to install ESSs on four of its platform support vessels working in the Gulf of Mexico.

According to Corvus, during 2017 it has experienced a 350% increase in orders from oil and gas sector and has observed that the total market energy storage installations in platform support vessels have grown by 217%.

BenefitsRetrofitting an energy storage system can be beneficial for dynamic positioning vessels. Since a non-hybrid vessel utilising dynamic positioning, will normally use two or more engines at a time to provide backup power, resulting in a low engine load that is inefficient and can result in increased emissions. However, using energy storage systems to provide backup power instead means that the operational engine closer optimal.

It has been estimated by Corvus energy that a platform support vessels equipped its orca energy storage system could see running hours 10 to 30%, fuel consumption cut by 15 to 20% CO2 emissions between 15 to 20% and NOx emissions reduced by 25 to 35%. According to Corvus website a whole range types of vessels being equipped its technology including fishing vessels, car ferries, tankers and research vessels.

Elsewhere, SolstadFarstad, and operator of offshore support vessels as had two of its vessels converted for hybrid operation by Westcon Power & Automation. In May this year agreed for a further two of its vessels to be converted in the same manner. SolstadFarstad’s COO Tor Inge Dale said that the company hybridised these vessels at the client’s request, which provides financial support for projects that aim to reduce NOx emissions. Part of the funding for converting has been supplied by Norway’s NOx fund, which launched a programme in September 2017 whereby PSVs on long-term contracts in Norway could apply for a fixed payment of Nkr5M towards retrofitting battery systems, with additional support of Nkr4 per kWh of charged shore power over a period of one year. A total of NKr100M was made available under the scheme, which had a deadline of 30 June 2018.

Old vessels, new ideasDue to the downturn in the offshore gas sector there are high number of redundant oil support vessels not in use into new uses but equipped with energy storage systems, such as mobile oceangoing power plants, natural gas tankers and even floating storage and regasification units.

One company Norwegian-based SolstadFarstad, suggested converting platform support vessels into mobile oceangoing power plants. In the Seatres’ design proposal, which is based around converting an Ulstein 745 class platform support vessel into a SeaKraft power-ship, which could moor up at offthe-grid locations, such as remote communities or projects, to meet short- or long-term power demands? The design envisages each SeaKraft fitted with between six and eight heavy fuel oil or diesel generators, with exhaust emissions management able to meet IMO’s tier 3 (diesel) standards. The design can provide up to 60MW to produce up to 500GWh annually per unit. The advantage that inclusive self-propelled unit, with generators, high voltage distribution, fuel storage, accommodation, power management and grid connection all handled on board.

Another proposal is by Norwegian company Cryo-Shipping, it proposes converting the full support vessels into small liquid natural gas tankers.

Another Norwegian company, is working on converting PSVs into many LNG tankers, using DP systems for safe, which is ideal for at-sea bunkering.

Meanwhile British virgin Island-based Dreifa Energy, as suggested converting such vessels into floating regasification units as already proposed for platform support vessels Blue Betria, which it received approval in principle from DNV GL in late 2017.